Simultaneous enrichment detection method for four types of pathogenic bacteria in food

Abstract

Recently, the incidence of foodborne disease outbreaks associated with contaminated meat, seafood and fresh produce has increased worldwide. Enterohaemorrhagic Escherichia coli (EHEC) O157:H7, Salmonella spp., Listeria monocytogenes and Shigella spp. have been responsible for recent outbreaks associated with the consumption of such contaminated food. Hence, suitable detection methods for monitoring the risk of microbial food contamination are necessary. These bacterial pathogens in food could be detected by enrichment culture in buffered peptone water (BPW) and multiplex PCR analysis of culture broth. After the detection of pathogens by multiplex PCR analysis, each pathogen-positive sample was cultured in an enriched selective broth. After the selective enrichment culture, the culture broth was plated on a selective agar plate to obtain colonies. EHEC (≧ 13 cells/25 g), S. Enteritidis (≧ 15 cells/25 g), L. monocytogenes (≧ 394 cells/25 g) and S. sonnei (≧ 2.4 cells/25 g) were detected and isolated. These pathogenic bacteria in frozen foods were also detected and isolated.